Lewis12 describes the hazards of breathing air containing
appreciable amounts of an asphyxiant (a gas that has no specific
toxicity but, when inhaled, excludes oxygen from the lungs). When
the mole percent of the asphyxiant in the air reaches 50%, marked
symptoms of distress appear, and at 75% death occurs in a matter of
minutes.

A small storage room whose dimensions are 2 m * 1.5 m * 3 m
contains a number of expensive and dangerous chemicals. To prevent
unauthorized entry, the door to the room is always locked and can
be opened with a key from either side. A cylinder of liquid carbon
dioxide is stored in the room. The valve on the cylinder is faulty
and some of the contents have escaped over the weekend. The room
temperature is 25°C.

(a)
IftheconcentrationofCO2reachesthelethal75mole%level,whatwouldbethemolepercentofO2?

(b) How much CO2 (kg) is present in the room when the lethal
concentration is reached? Why would more than that amount have to
escape from the cylinder for this concentration to be
reached?

(c) Describe a set of events that could result in a fatality
in the given situation. Suggest at least two measures that would
reduce the hazards associated with storage of this seemingly
harmless substance.